Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Limited proteolysis of catalytic and regulatory subunits of cyclic AMP-dependent protein kinase (A-pk), cyclic AMP phosphodiesterase, glycogen synthase, and histones by fungal protease (type XIX) was analyzed by the digested peptide bands in SDS polyacrylamide gel electrophoresis. The modulatory effects on proteolysis by nucleotides, polypeptides, and phospholipids may greatly depend on the intrinsic nature of substrates. The proteolysis of the regulatory subunit of A-pk and glycogen synthase was not regulated by nucleotides and nucleic acids. In comparison, phosphatidyl serine, cardiolipin, and pepstatin A stimulated the proteolysis of the catalytic subunit of A-pk. Whereas, lambda DNA (Hind III digest), t-RNA, GTP-, phosphatidyl serine, sphingosine inhibited the proteolysis of cyclic AMP phosphodiesterase. Moreover, MS2 RNA, lambda DNA, t-RNA, dGTP, Phosphatidyl serine, phosphatidyl inositol, antipain, and chymostatin exerted inhibitory proteolytic effect on histone VIII-S. Some of these agents also had similar inhibitory effect on other types of histones (types III-S and VII-S). The inhibitory effect of phosphatidyl serine on proteolysis of histone may be due to their interaction which was monitored by the drastic increase of uv absorbance.
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PMID:Regulation of fungal proteolysis on cyclic AMP-dependent protein kinase, cyclic AMP phosphodiesterase, glycogen synthase and histones. 165 82

The regulatory subunit of cAMP-dependent protein kinase in yeast, encoded by the BCY1 gene, is known to be required under certain conditions such as growth on nonfermentable carbon sources and entry into stationary phase. We have identified novel isoforms of Bcy1 in cells under these conditions. The isoforms are distinguishable by their migration on one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and 2-dimensional nonequilibrium pH gradient gel electrophoresis. The isoforms observed by one-dimensional SDS-PAGE bind cAMP, as determined by [32P]8-azido-cAMP labeling (diagnostic of Bcy1 protein). Proteins isolated from cells grown to stationary phase in rich medium exhibit five antibody-reactive bands, by one-dimensional SDS-PAGE immunoblot analysis, with apparent molecular masses of 50, 52, 55, 59 and 61 kDa. Total Bcy1 protein increases at least 8-fold between exponential and stationary phase. Analysis of proteins from a variety of yeast mutants indicated that 1) many of the observed modifications of Bcy1 are dependent upon the presence of the Ser-145 phosphorylation site; 2) the appearance of the 59- and 61-kDa bands is dependent upon the presence of Yak1 kinase; and 3) Bcy1 protein is modified even in the absence of cAMP-dependent protein kinase catalytic subunits. Cells carrying the bcy1(ala145) allele exhibit non-wild type growth, indicating that these modifications may be functionally significant.
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PMID:Bcy1, the regulatory subunit of cAMP-dependent protein kinase in yeast, is differentially modified in response to the physiological status of the cell. 165 93

Endogenous phosphorylation of proteins in cell suspensions of collecting tubes was studied. Using SDS disc electrophoresis in polyacrylamide gel with subsequent autoradiography, it was shown that vasopressin increases the 32P incorporation into two proteins with molecular masses of 15 kDa and 33 kDa, which serve as endogenous substrates for cAMP-dependent protein kinase. The hormone-dependent phosphorylation of these proteins was typical of the membrane fraction of collecting tube cells but was absent in the cytosolic fraction. The results obtained are suggestive of the direct involvement of vasopressin in the regulation of membrane protein phosphorylation by cAMP-dependent protein kinase which may increase the permeability of cells for H2O.
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PMID:[Phosphorylation of proteins in collecting tube cells under the effect of vasopressin]. 165 15

The lysosomal enzyme binding receptor protein isolated from monkey brain by phosphomannan-Sepharose affinity chromatography was phosphorylated by [gamma-32P] ATP by protein kinases tightly associated with the receptor protein. A greater than 200 kDa protein was phosphorylated on both serine and tyrosine residues and a approximately 45 kDa protein was phosphorylated on only serine residues as evidenced by SDS-gel electrophoresis, autoradiography and phosphoamino acid analysis [(Panneerselvam, Ramamoorthy & Balasubramanian (1987) Biochem Biophys Res Commun, 147, 927-935)]. 125I-labelled lysosomal enzymes could be cross-linked to the receptor protein in the presence of disuccinimidyl suberate. Phosphorylation of the receptor on both serine and tyrosine residues was inhibited by quercetin, polylysine and polymyxin B. Catalytic subunit of cyclic AMP-dependent protein kinase preferentially phosphorylated the approximately 45 kDa protein. In the presence of Triton X-100, phosphorylation of a few additional protein bands on non-tyrosine residues was observed. There was a marked reduction in the efficiency of binding lysosomal enzymes by the phosphorylated receptor protein in comparison to the unphosphorylated receptor protein.
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PMID:Lysosomal enzyme binding receptor protein from monkey brain and its phosphorylation. 166 94

Epstein-Barr virus encodes two small RNAs, EBER-1 and -2, that are abundantly expressed in latently infected cells. Recent evidence suggests a role for EBER-1 in regulation of translation since this RNA is able to prevent the inhibition of protein synthesis by double-stranded RNA in rabbit reticulocyte lysates. We show here that EBER-1 that has been synthesized in vitro forms a complex with the dsRNA-activated inhibitor of protein synthesis DAI, a protein kinase that specifically phosphorylates polypeptide chain initiation factor eIF-2. Gel retardation assays and UV crosslinking experiments indicate that complex formation is specific for EBER-1 and requires the presence of some secondary structure in the molecule. RNA competition studies show that EBER-1-DAI complex formation is not inhibited in the presence of other small RNA species, heparin or the synthetic double-stranded RNA, poly(I).poly(C). SDS gel analysis reveals the existence of two forms of the crosslinked complex, of 64-68kDa and 46-53kDa, both of which are recognized by anti-DAI antibodies in immunoprecipitation experiments. These data suggest that EBER-1 regulates protein synthesis through its ability to interact with DAI.
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PMID:Binding of Epstein-Barr virus small RNA EBER-1 to the double-stranded RNA-activated protein kinase DAI. 167 26

Limited proteolysis of tyrosine hydroxylase (TH) by calpain, Ca(2+)-activated neutral protease, was studied. Cleavage of TH with calpain in vitro produced molecules having Mrs of approximately 57,000 and 56,000 in SDS-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence, Ser-Pro-Arg-Phe-Val, of the 56-kDa species indicated that calpain cleaved off the N-terminal region (residues 1-30) encoded by the first exon including Ser-8 and Ser-19, the phosphorylation sites by proline-directed protein kinase (PDPK) and by Ca2+/calmodulin-dependent protein kinase II (kinase II), respectively, from the native TH. The removal of the N-terminal region from the native molecule induced a slight but significant activation of TH at pH 7.0. The native TH behaved as the tetramer with an Mr of 240,000. In contrast, calpain-cleaved TH showed the monomeric Mr by gel permeation chromatography and increased Ki for catecholamine which inhibits the native TH in competition to the coenzyme, DL-6-methyl-5,6,7,8-tetrahydropterin (6MPH4). These results imply that calpain cleavage would effectively release TH from the feedback inhibition by removal of the N-terminal region resulting in disruption of the quaternary structure.
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PMID:Limited proteolysis of tyrosine hydroxylase by Ca(2+)-activated neutral protease (calpain). 168 1

Tyrosine hydroxylase was purified in high yield from rat PC12 cells. This three-day procedure consisted of differential ammonium sulfate precipitation, anion-exchange chromatography, and heparin-Sepharose affinity chromatography. It yielded an average of 15 mg of purified protein from 100 flasks of PC12 cells, with greater than 40% recovery of tyrosine hydroxylase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis yielded a single protein band with a molecular weight of approximately 60,000. The protein had a specific activity of 670 nmol/min/mg and had a Km for its reducing cofactor tetrahydrobiopterin of 1.8 mM. The purified protein can be phosphorylated and activated by cyclic AMP-dependent protein kinase.
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PMID:Tyrosine hydroxylase purification from rat PC12 cells. 168 81

Recently we reported the purification of a mitogen-activated S6 kinase from Swiss mouse 3T3 fibroblasts and rat liver. The rat liver protein was cleaved with cyanogen bromide or trypsin and 17 of the resulting peptides were sequenced. DNA primers were generated from 3 peptides that had homology to sequences of the conserved catalytic domain of protein kinases. These primers were used in the polymerase chain reaction to obtain a 0.4-kilobase DNA fragment. This fragment was either radioactively labeled and hybridized to Northern blots of poly(A)+ mRNA or used to screen a rat liver cDNA library. Northern blot analysis revealed four transcripts of 2.5, 3.2, 4.0, and 6.0 kilobases, and five S6 kinase clones were obtained by screening the library. Only two of the clones, which were identical, encoded a full-length protein. This protein had a molecular weight of 56,160, which correlated closely to that of the dephosphorylated kinase determined by SDS/PAGE. The catalytic domain of the kinase resembles that of other serine/threonine kinases belonging to the second messenger subfamily of protein kinases.
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PMID:Cloning of the mitogen-activated S6 kinase from rat liver reveals an enzyme of the second messenger subfamily. 169 26

The hematoxylin-stainable protein (HSP) in keratohyalin granules of the newborn rat epidermis was found to have the same amino acid composition and the same inhibitory and immunological properties as cystatin alpha. However, only its pI value (4.7) differed from that of cystatin alpha (5.3). Alkaline phosphatase treatment of HSP changed its pI value from 4.7 to 5.3. This pI change was inhibited by EDTA, an inhibitor of alkaline phosphatase. Furthermore, 32P from [gamma-32P]ATP was incorporated into recombinant cystatin alpha by a protein kinase C (PKC) preparation in the presence of phosphatidyl serine and Ca2+ ions as co-factors. The incorporation increased dose-dependently with the added cystatin alpha and was inhibited significantly by H-7, a specific inhibitor of PKC. SDS-PAGE autoradiography of the 32P-labeled proteins showed that 32P was incorporated into the cystatin alpha. This incorporation was not observed by the action of cAMP-dependent protein kinase. Therefore, it is highly possible that the HSP is a phosphorylated cystatin alpha and that the phosphorylation is catalyzed specifically by PKC.
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PMID:Identification of hematoxylin-stainable protein in epidermal keratohyalin granules as phosphorylated cystatin alpha by protein kinase C. 171 84

Nitric oxide synthase was purified to apparent homogeneity from the cytosolic fractions obtained from rat and porcine cerebellum. Enzyme activity--measured as [3H]citrulline formation after incubation with [3H]arginine--was dependent on Ca2+/calmodulin, NADPH, and tetrahydro-L-biopterin. Specific activity varied between 450 to 780 nmol/min/mg protein. Purified nitric oxide synthases showed a single band on 8% SDS/PAGE gels and had an apparent molecular mass of 150,000 Da. The purified proteins were used as substrate for phosphorylation with different protein kinases. In the assays using two Ca2+/calmodulin-dependent protein kinases, CaM kinase II and CaM kinase-Gr, protein kinase C, and the catalytic subunit of protein kinase A, nitric oxide synthase was exclusively phosphorylated by protein kinase A. Such phosphorylation was linear over time for at least 60 min and resulted in nearly stoichiometric phosphate/protein incorporation. The serine in the protein kinase A-consensus sequence KRFGS is probably the site of phosphorylation in nitric oxide synthase. Kemptide, a known protein kinase A substrate, inhibited phosphorylation of nitric oxide synthase in a dose-dependent manner. No changes in nitric oxide synthase activity were observed upon phosphorylation by protein kinase A.
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PMID:Phosphorylation of nitric oxide synthase by protein kinase A. 172 13


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